Jaw crusher units typically comprise a fixed jaw and a movable jaw that define a crushing zone therebetween and a drive mechanism operative to rock the movable jaw back and forth in order to crush material in the crushing zone.
The crushing zone defined between the fixed jaw and the movable jaw is generally convergent towards its lower discharge end so that crushable material fed to the upper and wider end of the zone is then capable of falling downward under gravity whilst being subject to repeated cycles of crushing movement in response to the cyclical motion of the movable jaw. The crushed material is then discharged under gravity through the narrower lower discharge end onto a conveyor belt for onward processing or final discharge from the crusher unit to a suitable stock pile.
Commonly, the frame that supports the fixed and movable jaws is referred to as the front frame end. The front frame end of the movable jaw is connected to what is typically referred to as a back frame end via a mechanically actuated link mechanism that serves to control and stabilise the oscillating movement of the movable jaw relative to the stationary jaw. Typically, the link mechanism is both statically and dynamically linearly adjustable to control the grade or size of the resultant crushed material, to facilitate absorption of the impact forces generated by the crushing action and to expand or open the crushing zone to prevent damage to the crusher in the event of non-crushable material being accidentally introduced into the crushing zone.
Example jaw crushers comprising linkage assemblies connecting the back frame and front frame ends are described in FR 2683462; EP 0773067; WO 97/36683; U.S. Pat. No. 5,799,888; WO 02/34393; WO 2008/010072 and JP 2009-297591.
The assembly and construction of jaw crushers particularly at the back frame and front frame regions is a compromise between strength and weight. On the one hand the crusher must be sufficiently robust with various components having the required stiffness to withstand the significant loading forces created and transmitted to the jaw crusher. On the other hand, manufacture, transportation and use of very heavy crushers is undesirable.
There is therefore a requirement for a jaw crusher and in particular a jaw crusher support frame that addresses the above problems.